Control device

ABSTRACT

A control device, useful in the manufacture of electronic air filter cells, is provided which controls movement of a plate holding fixture. The device is synchronized with a plate manufacturing machine, for example, a punch press so that plates can be fed from the manufacturing machine to the fixture. The device includes a skip mechanism which permits two strokes of the plate manufactured machine for each movement step of the control device.

lJnited States Patent [1 1 Gebhart et al.

[ CONTROL DEVICE [75] Inventors: Howard C. Gebhart, Chesterfield;

Nick Tichy, Affton, both of Mo.

1 [73] Assignee: Emerson Electric Co., St. Louis, M0.

22 Filed: Feb. 22, 1973 21 Appl.No.:334,893

[52] US. Cl. 74/116 [51] Int. Cl. Fl6h 29/00 [58] Field of Search 74/1'16, 117

[56] References Cited UNITED STATES PATENTS 2,234,094 3/194] Sprinkle....'. 74/ll6 350,597 l'0/l 886 Meeker 74/l16 [451 Apr. 16, 1974 2,933,931 4/1960 Lisinski 74/116 Primary Examiner-Samuel Scott Assistant Examiner-Wesley S. Ratliff, Jr.

Attorney, Agent, or Firm-Polster and Polster 57] ABSTRACT A control device, useful in the manufacture of electronic air filter cells, is provided which controls movement of a plate holding fixture. The device is synchronized with a plate manufacturing machine, for exam ple, a punch press so that plates can be fed from the manufacturing machine to the fixture. The device includes a skip mechanism which permits two strokes of the plate manufactured machine for each movement step of the control device.

15 Claims, 4 Drawing Figures PMENTEBAPR ms 974 SHEEY 2 (If 4 FATENTEDAPR 16 I974 SHEET 5 BF 4 FIG. 4.

CONTROL DEVICE BACKGROUND OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS This invention relates to a control device, and in pan 5 plication for the control device of this invention;

ticular to a device useful in apparatus for constructing electronic air filter cells. While the invention is particularly applied to electronic air'filter cell construction, those skilled in the art will recognize the side applicability of this invention to other control applications.

It is conventional, in the construction of electronic air filter cells, to fabricate a series of plates having a plurality of openings in them. The plates conventionally are constructed from sheet aluminum, generally being formed by some type of punch press operation.

7 The press punches both a predetermined plate site and a plurality of openings through the plates.

There long has been a desire to automate and combine the plate manufacture process with filter cell construction. A method for this combination is disclosed in the co-pending Wightman et al. U.S. application Ser. No. 327,0l8 filed Jan. 26, 1973. It is desirable, in automated cell manufacturing, to feed the cell plates directly from a punch press to a fixture for holding the plates. Although a variety of fixtures are suitable for this reception, at fixture designed with several specific advantages useful in cell construction is disclosed in the copending Wightman U.S. application Ser. No. 327,083 filed Jan. 26, 1973.

The device disclosed hereinafter permits control of a fixture in relation to another'manufacturing apparatus, preferably a punch press, so that the fixture movement is coincident with manufacturing apparatus operation.

One of the objects of this invention is to provide a control device for a fixture used in the manufacturing of electronic air filter cells.

Another object of this invention is to provide a control device which coordinates operation of a first apparatus with movement of a second apparatus.

Another object of this invention is to provide a low cost control device for regulating movement.

Still another object of this invention is to provide a timing device which automatically provides for a lost motion step in its operation.

Other objects will be apparent to those skilled in the art in light of the following description and accompanying drawings.

SUMMARY OF THE INVENTION In accordance with this invention, generally stated, a control device is provided for coordinating movement of a cell plate fixture in relation to a first manufacturing step.

In the preferred embodiment, the cell plate fixture receives cell plates which are later combined with tubular structures to form an electronic air filter cell. The fixture is controlled by the apparatus of this invention so as to permit plates, manufactured from a conventional punch press, to be inserted within the fixture as they are manufactured. The control device provides for a lost movement step so that pairs of plates may be inserted into a particular position within the fixture. The device also has antibacklash means associated with it which prevents loss of fixture control in the event of power failure.

FIG. 2 is an enlarged view taken along the line 2-2 of FIG. 1;

FIG. 3 is a sectional view taken along the line 33 of FIG. 2; and

FIG. 4 is a sectional view taken along the line 44 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, reference numeral 1 indicates the control device of this invention. The device 1 is illustratively shown in an application where electronic air filter cells are manufactured. In the manufacture of these cells, it is desirable to feed a plurality of plates manufactured by a punch press, generally indicated by the numeral 2, having an output side 3 which feeds the plates to a conveyor, generally indicated by the numeral 4. The conveyor 4 preferably is a pawltype transfer conveyor whose feed length can be adjusted for different plate widths. However, other conveyor types are suitable for use with the control device 1. The conveyor 4 is timed so that a manufactured cell plate, not shown, will reach an end 76 of the conveyor 4 as a newly manufactured plate leaves the output 3 of the punch press 2 during normal, extended operating periods.

The conveyor 4 feeds plates under controlled conditions to a plate fixture 5. As indicated above, a fixture particularly suitable in applications of this type is described in the co-pending Wightman U.S. application Ser. No. 327,083 filed Jan. 26, I973. Fixtures of the class of which fixture 5 is illustrative commonly weigh in the vicinity of two thousand pounds. In the particular application illustrated in FIG. 1, the fixture 1 is supported on a structure 6. The fixture is raised to an upper position along a central portion of the structure 6 by hydraulic means, not shown. Thereafter, the control device I lowers the fixture 5 at discrete intervals, against the lifting force of the hydraulic means. As the fixture 5 is lowered, plates from the punch press 2 are inserted in it. When the fixture reaches a-lower position along the structure 6, it is shifted to a second station outboard of the central portion of the structure 6 and rotated to a horizontal attitude by rotation means 77. Rotation means 77 is conventional and is not described in detail. Those skilled in the art will recognize that a number of mechanical components are available for performing rotation of the fixture 5. We find it convenient to power rotation means 77 by hydraulic means not shown, but other power sources are compatible with the broader aspects of our invention. Rotation of the fixture 5 positions the fixture along an insertion area portion of the apparatus generally indicated by the numeral 7. Several constructional steps are accom-' plished at the area 7. For example, tubular structures can be inserted through the openings in the plates and expanded to form an integral tubular structure-cell plate combination. Apparatus for tube insertion and expansion is disclosed in the co-pending Wightman United States application Ser. No. 327,244 filed Jan. 26, 1973.

The support structure 6 includes a conventional frame 8 having a pair of spaced side beams 9 connected to respective ends of top beam 10. The beam pair 9 are conventional U-shaped channel beams. The spacing between the beam pair 9 may vary. The embodiment illustrated uses sufficient spacing to provide a central portion for fixture loading and an outboard station on each side of the central portion for fixture rotation to separate areas 7 where insertion and expansion of the tubular structure is accomplished.

A carriage assembly 11 is supported by the frame 8 along the central portion of the beam 10. Carriage assembly 11 has the fixture 5 removably mounted on it. A pair of guide rods 12 extend along the vertical height of the frame 8. The guide rods 12 are conventional tubular structures, and the carriage assembly 11 is movably mounted to the rods 12 by any convenient method. Conventional slip fit bearings work well, for example. A hydraulic power means, not shown, is operatively connected to the carriage assembly 11 and is adapted to drive the carriage assembly 11, and consequently the fixture 5 in a vertical direction, as referenced to FIG. 1 of the drawings.

A support plate 13 is mounted to structure 6 by any convenient method. Generally, component parts of the apparatus of this invention may be secured to one another by conventional threaded fasteners. Other attachment means and methods are compatible with the broader aspects of the invention.

Support plate 13 is used as a base for the control device l. The support plate 13 has a plurality of openings in it, which are not represented by reference numerals, but which are used to permit passage of certain structural components of the control device 1 as explained hereinafter.

Carriage assembly 11 has a pair of racks indicated by the numbers 14 and 15 attached to it. The rack 14 is a conventional structure having a plurality of teeth 16 extending outwardly from a body portion 17. The rack 15 likewise includes a body portion 18 having a plurality of teeth 19 extending outwardly from it. The teeth 16 and 19 are arranged oppositely with respect to one another, as is best observed in FIG. 3. This arrangement is important in the operation of the device 1 as is later set forth. The racks l4 and 15 preferably are arranged adjacent to one another, as illustrated in FIG. 2. Adjacent construction is preferred in that the operation of device 1 is simplified by such placement. However, other constructions may utilize spaced racks rather than the arrangement shown.

Referring now to FIGS. 2 and 3, it may be observed that a drive means 20 is operatively connected to the control device 1. Drive means 20 is aconventional pulley assembly including a sheave 21 and a drive belt 22. The sheave 21 is mounted to a shaft 23. The drive belt 22 is attached to the sheave 21 on one end, and has a second end driven by a sheave on a right angle miter gear box, not shown, which is driven by a drive shaft, not shown, connected to the press 2 crank shaft to synchronize the drive means 20 with the press 2. The shaft 23 in turn is operatively connected to an input shaft mechanism 24. Input shaft mechanism 24 includes a gear 25 shown in outline in FIG. 3. Though shown in outline, those skilled in the art will understand that the gear 25 has a conventional toothed wheel configuration. The input shaft mechanism 24 is connected to a drive mechanism 26 and a cam assembly mechanism 27 by a pair of gears 28 and 29 respectively.

The gears 28 and 29 also are conventional gear wheels having teeth which intermesh with the teeth of the gear 25 but which are shown in outlined in FIG. 3. In the embodiment illustrated, the gears 28 and 25 are in a one to one gear ratio while the gears 25 and 29 are in a two to one gear ratio. That is, the gear 29 makes half a revolution for each revolution of the gear 25.

The drive mechanism 26 includes a shaft 30 and a connecting rod 31 mounted on the shaft 30 and mov able therewith. The shaft 30 is driven by the gear 28 which, as indicated above, is controlled through the shaft mechanism 24 by drive means 20. The shaft 30 uses an adjustable crank pin, not shown, to drive connecting rod 31. The crank pin is eccentric to the shaft 30 center line. Consequently, rotation of the gear 28 will impart both left-right and up-down motion, with respect to FIG. 3, to the connecting rod 31.

Connecting rod 31 is a conventional connecting rod. The rod 31 has a lower connection part 32 having an opening 33 in it. The opening 33 is used to mount a pawl assembly 34 to the connecting rod 31.

Pawl assembly 34 includes a connecting arm 35 and a pawl 36. The connecting arm 35 is L-shaped in side elevation, having a short leg 37 and a long leg 38. The leg 37 has a pintle part 39 extending outwardly from it which enters the opening 33 in the connecting rod 31, permitting mounting of pawl assembly 34 with the rod 31.

The long leg 38 of arm 35 likewise has a pintle part 40 extending outwardly from it. The pintle part 40 is utilized for interconnecting the pawl 36 with the connecting arm 35.

Pawl 36 has an elongated body 41 having an opening 42 through it. The opening 42 engages the pintle part 40 and is used to mount the pawl 36 on the connecting arm 35. Pawl 36 is movable with the arm 35 and is rotatable about the part 40-opening 42 connection. Body 41 has a pad 43 formed on a first end of it, and a ratchet point 44 formed on a second end but on an opposite side of the body 41.

As indicated, the pawl 36 is free to pivot about the pintle part 40 in response to external force stimuli, described hereinafter. The ratchet part 44 of pawl 36 is sized to fit between adjacent teeth 16 of rack 14, as is observable in FIG. 3. This engagement is important and is primarily responsible for the controlled lowering of the carriage assembly 11. That is, rotation of drive means 20, which as previously indicated is timed to the punch press 2, will cause rotation of drive mechanism 26. Rotation of drive mechanism 26 in turn, because of the gear 25-gear 28, imparts both left-right and updown motion to the pawl 36. This motion successively disengages the ratchet part 44 from the rack 14, raises the pawl 36 to the next tooth 16 in the rack 14, reinserts the ratchet part 44 in a succeeding tooth l6, and drives the rack 14 downwardly one tooth space as the drive mechanism 26 responds to the drive means 20 input from the punch press 2. As an aid in ratchet 44 reinsertion in the succeeding tooth 16, the embodiment illustrated uses a spring means 45 to back bias the pawl Spring means 45 includes a casing 47 having an opening 78 in it. The opening 78 is closed within the casing 47 by a bottomwall 80. The opening 78 receives a plunger 79 in a free, slip fit. Plunger 79 is a tubular structure having a tip 81 closing a channel 82 in the plunger 79. The channel 82 is open on an end 93 opposite the top 81. A spring 46 is inserted within the opening 78 and is mounted in the channel 82 of plunger 79. The spring 46 is compressed between the wall 80 and the tip 81 so as to bias the tip 81 against the body 41 of the pawl 36, which forces the ratchet part 44 of the body into engagement with the rack 14, between the teeth 16 of the rack 14.

As previously indicated, the carriage assembly 11 is lifted into its initial starting position hydraulically. This upward hydraulic pressure is maintained on the carriage assembly 11 throughout the operation of the control device 1. The drive mechanism 26 and paw] assembly 34 are designed to overcome this positive pressure and to force the carriage assembly downwardly in incremental steps. As indicated, it is desirable, with certain fixtures utilized in the production of electronic air filter cells, to skip alternate strokes of the punch press 2 in the sequenced lowering of the carriage assembly 11. Toward this end, the cam assembly mechanism 27 is designed to provide lost motion control for the apparatus of this invention.

Cam assembly mechanism 27 includes the gear 29, a cam plate 48, a pair of support blocks 49, a rod 50, and a pad 51.

The support blocks 49 each have an opening in them. The rod 50 is mounted to the blocks 49 through the openings in the respective blocks 49. The rod 50 also is operatively connected to the pad 51. Connection may be made by any convenient method. The parts may be formed integrally or the pad 51 may have a threaded opening in it for receiving a threaded end of the rod 50, for example. Pad 51 includes a front face 52 which is adapted to abut the pad 43 of the pawl 36 as described below. The cam plate 48 has an upper surface 83 having a race way 84 in it. The blocks 49 are mounted to the plate 48 and are freely movable along the race way 84 in a left-right direction as referenced to FIG. 3. Thegear 29 is operatively connected to the blocks 49 by any convenient method. For example, an arm may be operatively connected between the gear 28 and the blocks 49 so that rotation of the gear 28 imparts left-right motion to the support blocks, and consequently the rod 50, as the arm follows rotation of the gear 29. The two to one relationship between the gears and 29 means that two rotations of the gear 25, corresponding to two strokes of the press 2, result in a single rotation of the gear 29. One rotation of gear 29 reciprocates the blocks 49 from an initial position where the pad 51 is disengaged from the pad 43 of the pawl 36 to a second position where the pad 51 engages the pad 43 and clears the ratchet 44 from between the teeth 16 of the rack 14 and then back to the initial position. Drive mechanism 26, of course, continues to operate as described above. However, the pawl 36 strikes air rather than the teeth l6of rack 14 or alternate rotations of the gear 28 because of the operation of the cam assembly mechanism 27. Other connecting methods are suitable for use between the gear 29 and blocks 49 provided they permit the timed movement of the rod 50 from a first position free of the pad 43 of the pawl 36 to a second position where the pad 51 meets the pad 43 and moves the pawl 36 about the pivot of pintle part 40 so as to disengage the ratchet 44 from between the teeth 16.

As thus described, rotation of drive means 20 by the punch press 2 always causes the pawl 36 to move left to right so as to disengage it from between the teeth 16 of the rack 14. However, on alternate strokes of the press 2, the cam assembly 27 engages the pad 43 of the pawl 36 and moves the pawl 36 so that it is reinserted between the same teeth 16. Consequently, a mechanism is disclosed permitting a lost motion or movement period with respect to the operations of punch press 2, and the fixture 5 which is attached'to the assembly 7, will maintain a single position for two strokes of the press 2. As described above, positive upward pressure is maintained on the carriage assembly 11. This upward pressure will prevent pawl 36 reinsertion between the same pair of teeth 16 unless means are provided to hold the carriage assembly in place during the lost motion time interval.

A gear 53 is operatively connected between the gear 29 of cam assembly 27 and a gear 54 in a stop and antibacklash pawl assembly 55. Gears 53 and 54 are conventional intermeshing tooth gears and are in a one gear ratio with respect to one another.

Stop and anti-backlash assembly 55 includes a cam assembly 56, an anti backlash assembly 57, and a stop assembly 58. Parts of the various assemblies comprising stop and anti-backlash assembly 55 utilized common connecting parts, as will be apparent from the following description.

The gear 54 is operatively connected to a cam plate 59, the plate 59 being rotatable with the gear 54. A follower 60 is operatively connected to the cam plate 59 and is movable therewith. A crank 61 includes an arm 95 having a slot 62 in it. The slot 62 is used to connect the crank 61 and the follower 6t], and thus the plate 59, to one another. A conventional threaded fastener 85 placed through an opening in the follower 60 works well for this connection, as the follower 60 is sized to overlap the edges delimiting the opening 62 in the arm 95. The follower 60 is free to move within the slot 62, imparting motion to the crank 61 when the follower 60 contacts a stop screw, not shown, mounted in an end 110 of crank 61. The crank 61 has a connection end 63 having a leg 87, shown in phantom lines, extending downwardly from the arm 95 giving the crank an L- shape in side elevation. The junction of the legs of the L-shaped crank 61 defines a pivot point 64. The point 64 has a pintle part 86 extending perpendicularly outwardly from it. A pawl 65 is mounted to the crank.6l along the pintle part 86. Pawl 65 is conventional and includes a body 88 having an opening in it. The pintle part 86 is placed through the opening in the body 88 in order to attach the pawl 65 to the crank 61. The downwardly extending leg 87 of crank-61, hidden in FIG. 3, has a connecting rod 66 extending outwardly from it along its free end. A pawl 67 has an opening 89 through it which is used to mount the pawl 67 to the connecting rod 66. The pawls 65 and 67 both have ratchet portions 69 and 68 respectively. The ratchet portion 68 of the pawl 67 is designed to engage the teeth 16 of rack 14. The ratchet portion 69 of the pawl 65 is designed to engage teeth 19 of the rack 15. Consequently, the pawls 65 and 67 are displaced from one another, which displacement is not easily observable in FIG. 3.

Stop assembly 58 also includes a pair of spring assemblies 70 and 98. Each spring assembly 70 and may be constructed similarly to the spring means'45 discussed above, and they are not discussed in detail. It is evident, from FIG. 3, that the spring assembly 70 has a spring 71 biasing a plunger 72 against an edge 73 of pawl 67 which tends to drive the pawl 67 into engagement with the teeth 16 of the rack 14 while the spring assembly 90 has a spring 91 biasing a plunger 92 against an edge 96 of pawl 65 into engagement with the teeth 19 of the rack 15.

Operation of the assembly 55 is coordinated to the other components of the control device 1 by the operation of the gears 53 and 54. As previously indicated, those gears are in a one to one ratio and they are designed so that the gear 54 makes two complete revolutions for each single revolution of the gear 29. The operation of the follower 60 in the slot 62, and thus the movement of crank 61 is such that the ratchet portion 68 of the pawl 67 is positioned between the teeth 16 of the rack 14 when the cam assembly means 27, and in particular when the pad 51 engages the pad 43, thereby preventing upward movement of the carriage 11, while the ratchet portion 68 of the pawl 67 is disengaged from between the teeth 16 when the ratchet portion 44 is engaging the teeth 16 of the rack 14 so as to drive the carriage assembly 11 downwardly. The pawl 65, on the other hand, is disengaged on each stroke of the press 2. This action is important as the anti-backlash portion prevents the carriage assembly 11 downward move ment, as for example during loss of hydraulic power while both the pawls 41 and 67 are disengaged from the teeth 16 of the rack 14.

Numerous variations, within the scope of the appended claims, will be apparent to those skilled in the art in light of the foregoing description and accompanying drawings. Thus, an enclosure, generally indicated by the numeral 75 in FIG. 3 may be positioned about the elements of the control device 1. Those skilled in the art also will recognize that various adjustments may be provided to permit the proper timing of the various gears comprising control device 1. The gear 29 may be selected so that any number of lost motion steps in relation to the driving means are obtained. Likewise, al-

though a punch press was used as the reference for the control device 1, other reference devices are compatible with the broader aspects of this invention. These variations are merely illustrative.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. A control device having repetitious mechanical command inputs comprising:

a support structure; drive means mounted to said support structure and operatively connected to said repetitious mechanical command inputs; means for moving an apparatus in a first direction in response to said repetitious mechanical command inputs, said moving means including first gear means rotatably mounted to said support structure and operatively connected to said drive means; means for automatically skipping apparatus movement on at least alternate ones of said repetitious mechanical command inputs, said skipping means including second gear means rotatably mounted to said support structure and operatively connected to said drive means; and means for maintaining apparatus position during operation of said skipping means mounted to said support structure and operatively connected to said drive means.

2. The control device of claim 1 wherein said apparatus comprises a plate spacing fixture, said supporting structure includes a carriage assembly having said plate spacing fixture mounted thereto, a first rack mounted to said carriage assembly, said rack including a body portion having a plurality of teeth extending outwardly from it; said moving means being further characterized by a first pawl assembly including a first pawl having a ratchet part, said first pawl assembly being operatively connected to said first gear means so that said first gear means imparts both horizontal and vertical motion to said pawl, said first pawl assembly being positioned so that rotation of said first gear means alternately inserts and retracts said ratchet part of said pawl assembly between the teeth of said first rack.

3. The control device of claim 2 wherein said skipping means is further characterized by means for biasing said first pawl during alternate sequential rotations of said first gear means, said biasing means being operative'ly connected to said second gearmeans.

4. The control device of claim 3 wherein said fixture has a second rack mounted to it, said second rack including a body portion having a plurality of teeth extending outwardly from it, and said means for maintaining fixture position comprises third gear means operatively connected so as to follow said repetitious mechanical command inputs including a third gear rotatably mounted to said supporting structure and a second pawl assembly including a second pawl having a ratchet portion, said second pawl assembly being arranged so that rotation of said third gear alternately inserts and retracts said second pawl from between the teeth of said first rack.

5. The control device of claim 4 wherein said fixture is further characterized by an anti-kickback assembly mounted to said supporting structure, said antikickback assembly comprising a third pawl operatively connected to said second pawl assembly, said third pawl having a'ratchet portion arranged so that rotation of said third gear alternately inserts and retracts said ratchet portion of said third pawl from between the teeth of said second rack.

6. A control device adapted to control movement of a plate spacing fixture during loading comprising:

a frame for supporting said fixture and said control device;

a carriage assembly movably mounted to said frame,

having said fixture attached to it;

a first rack mounted to said carriage assembly, said first rack including a body portion and a plurality of teeth extending outwardly from said body portion;

a first pawl mounted to said frame and engagable with said first rack;

a second pawl mounted to said frame and engageable with said first rack;

means for repetitiously commanding disengagement and reengagement of said first pawl and said first rack, said last mentioned means comprising first gear means including at least a first gear rotatably mounted to said frame and a first pawl assembly including said first pawl operatively connected to said first gear; and

means for disengaging said second pawl from said first rack on at least alternate ones of said repetitious disengagement commands.

9 I 7. The control device of claim 6'further characterized by a second rack mounted to said carriage assembly, said second rack including a body portion having a plurality of teeth extending outwardly therefrom, and

a third pawl mounted to said frame and engagable with said second rack. 1

8. The control device of claim 6 wherein said means i a first driven gear rotatably mounted to said support structure and operatively connected to said drive gear in a one to one ratio;

a first rack movable mounted to said supportstructure, said rack having a plurality of teeth formed in it;

a pawl operatively connected to said first'driven gear, said pawl having a part insertable between the teeth of said first rack;-

a second driven gear rotatably mounted to said support structure and operatively connected to said drive gear in a gear ratio other than a ratio of one to one; and

means for repositioning-said first paw] operatively connected to said second drive gear.

11. The control device of claim 10 wherein said gear ratio between said second driven gear and said drive gear is two to one.

12. The control device of claim 10 further characterized by a third driven gear rotatably mounted to said support structure and operatively connected to said drive gear, and a second pawl operatively connected to saidthird' driven gear, said second pawl having a part insertable between the teeth of said first rack.

13. The control device of claim 12 further characterized by a second rack movably mounted to said support structure, said rack having a plurality of teeth formed in it, and a third pawl operatively connected to said third driven gear, said third pawl having a part insertable between the teeth of said second rack.

14. The control device of claim 13 wherein each of said first, said second and said third pawls are biased toward engagement with respective ones of said first and said second racks.

15. A control device comprising:

a support structure;

drive means rotatably mounted to said support structure and operatively connected to a power source;

first driven means rotatably mounted to said support structure and operatively connected to said drive means for coincidental rotational movement therewith; first engageable means movably mounted to said support structure;

' engagement means operatively connected to said means.

Patent No. 9 3 Dated April 97 Inventofls) Howard C. Gebhart and Nick 'Iichy It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below;

Column 6, line 21, after "and are in a one" insert to one Signed and sealed this 13th day of August 1974.

(SEAL) Attest:

MCCOY M. GIBSON, JR. C. MARSHALL DANN Attesting Officer Commissioner of-Patents FORM PO-1050 (10-69) USCOMM DC 6376 p69 u.s. GOVERNMENT PRINTING OFFICE I969 0-366-334. 

1. A control device having repetitious mechanical command inputs comprising: a support structure; drive means mounted to said support structure and operatively connected to said repetitious mechanical command inputs; means for moving an apparatus in a first direction in response to said repetitious mechanical command inputs, said moving means including first gear means Rotatably mounted to said support structure and operatively connected to said drive means; means for automatically skipping apparatus movement on at least alternate ones of said repetitious mechanical command inputs, said skipping means including second gear means rotatably mounted to said support structure and operatively connected to said drive means; and means for maintaining apparatus position during operation of said skipping means mounted to said support structure and operatively connected to said drive means.
 2. The control device of claim 1 wherein said apparatus comprises a plate spacing fixture, said supporting structure includes a carriage assembly having said plate spacing fixture mounted thereto, a first rack mounted to said carriage assembly, said rack including a body portion having a plurality of teeth extending outwardly from it; said moving means being further characterized by a first pawl assembly including a first pawl having a ratchet part, said first pawl assembly being operatively connected to said first gear means so that said first gear means imparts both horizontal and vertical motion to said pawl, said first pawl assembly being positioned so that rotation of said first gear means alternately inserts and retracts said ratchet part of said pawl assembly between the teeth of said first rack.
 3. The control device of claim 2 wherein said skipping means is further characterized by means for biasing said first pawl during alternate sequential rotations of said first gear means, said biasing means being operatively connected to said second gear means.
 4. The control device of claim 3 wherein said fixture has a second rack mounted to it, said second rack including a body portion having a plurality of teeth extending outwardly from it, and said means for maintaining fixture position comprises third gear means operatively connected so as to follow said repetitious mechanical command inputs including a third gear rotatably mounted to said supporting structure and a second pawl assembly including a second pawl having a ratchet portion, said second pawl assembly being arranged so that rotation of said third gear alternately inserts and retracts said second pawl from between the teeth of said first rack.
 5. The control device of claim 4 wherein said fixture is further characterized by an anti-kickback assembly mounted to said supporting structure, said anti-kickback assembly comprising a third pawl operatively connected to said second pawl assembly, said third pawl having a ratchet portion arranged so that rotation of said third gear alternately inserts and retracts said ratchet portion of said third pawl from between the teeth of said second rack.
 6. A control device adapted to control movement of a plate spacing fixture during loading comprising: a frame for supporting said fixture and said control device; a carriage assembly movably mounted to said frame, having said fixture attached to it; a first rack mounted to said carriage assembly, said first rack including a body portion and a plurality of teeth extending outwardly from said body portion; a first pawl mounted to said frame and engagable with said first rack; a second pawl mounted to said frame and engageable with said first rack; means for repetitiously commanding disengagement and reengagement of said first pawl and said first rack, said last mentioned means comprising first gear means including at least a first gear rotatably mounted to said frame and a first pawl assembly including said first pawl operatively connected to said first gear; and means for disengaging said second pawl from said first rack on at least alternate ones of said repetitious disengagement commands.
 7. The control device of claim 6 further characterized by a second rack mounted to said carriage assembly, said second rack including a body portion having a plurality of teeth extending outwardly therefrom, and a third pawl mounted to said frame and engagaBle with said second rack.
 8. The control device of claim 6 wherein said means for disengaging said second pawl from said first rack comprises second gear means including a second gear rotatably mounted to said frame, and a second pawl assembly including said second pawl operatively connected to said second gear.
 9. The control device of claim 8 wherein said first gear makes two revolutions for each revolution of said second gear.
 10. A control device comprising: a support structure; a drive gear rotatably mounted to said support structure and operatively connected to a power source; a first driven gear rotatably mounted to said support structure and operatively connected to said drive gear in a one to one ratio; a first rack movable mounted to said support structure, said rack having a plurality of teeth formed in it; a pawl operatively connected to said first driven gear, said pawl having a part insertable between the teeth of said first rack; a second driven gear rotatably mounted to said support structure and operatively connected to said drive gear in a gear ratio other than a ratio of one to one; and means for repositioning said first pawl operatively connected to said second drive gear.
 11. The control device of claim 10 wherein said gear ratio between said second driven gear and said drive gear is two to one.
 12. The control device of claim 10 further characterized by a third driven gear rotatably mounted to said support structure and operatively connected to said drive gear, and a second pawl operatively connected to said third driven gear, said second pawl having a part insertable between the teeth of said first rack.
 13. The control device of claim 12 further characterized by a second rack movably mounted to said support structure, said rack having a plurality of teeth formed in it, and a third pawl operatively connected to said third driven gear, said third pawl having a part insertable between the teeth of said second rack.
 14. The control device of claim 13 wherein each of said first, said second and said third pawls are biased toward engagement with respective ones of said first and said second racks.
 15. A control device comprising: a support structure; drive means rotatably mounted to said support structure and operatively connected to a power source; first driven means rotatably mounted to said support structure and operatively connected to said drive means for coincidental rotational movement therewith; first engageable means movably mounted to said support structure; engagement means operatively connected to said first driven means, said engagement means and said engagable means being removably interconnectable with one another; second driven means rotatably mounted to said support structure and operatively connected to said drive means, rotation of said second driven means being concurrent but not coincident with said drive means; and means for repositioning said first engagable means operatively connected to said second driven means. 